A-TECH 4GB KIT (2 x 2GB) For Dell XPS 420 710/710 H2C 710/710 H2C 720 720 H2C One 20 One 24. DIMM DDR2 NON-ECC PC2-6400 800MHz RAM Memory. Genuine Brand. 4GB KIT (2 x 2GB) DIMM DDR2 NON-ECC PC2-6400 800MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For Dell XPS. (See Compatibility List Below)